Pneumatic road roller



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H. J. SEAMAN PNEUMATIC ROAD ROLLER Jan. 9, 1962 Filed Jan. 25, 1956 MM M i E z n S m J w w f M Jan- 9, 1962 H. J. SEAMAN PNEUMATIC ROAD ROLLER 2 Sheets-Sheet 2 Filed Jan. 25, 1956 INVENTOR. H4RRY J. SEAMAN United States Patent 3,015,997 PNEUMATIC ROAD ROLLER Harry J. Seaman, Milwaukee, Wis. Filed Jan. 25, 1956, Ser. No. 568,952 2 Claims. (Cl. 94-50) (Filed under Rule 47(b) and 35 U.S.C. 118) This invention relates to a road roller and particularly is directed to a self-propelled road roller having a front and rear roller assembly provided by a series of pneumatic tired wheels or pneumatic rolls mounted upon a solid axle.

In general, the invention is directed to a road roller comprising a ballast section which is supported at the rear by a series of pneumatic rolls mounted to rotate freely on a common axle to provide the rear roller assembly. The ballast section is secured by a hitch to a front unit which supports the engine and driving mechanism on a series of pneumatic rolls mounted on a common axle and forming the front roller assembly. The rolls or wheels in front are lesser in number than the rear rolls and are offset from the rear rolls to roll over paths lying between corresponding pairs of the rear rolls.

The rear roller assembly is readily removed as a unit and the same is true of the front roller assembly.

The machine is driven through the front rollers by the engine mounted thereon and through suitable clutches for the individual pneumatic rollers on the axle.

An object of the invention is to provide an approach to a solid roller drum in a pneumatic roller by means of closely spaced tires on a solid axle.

Another object of the invention is to provide a road roller employing multiple pneumatic rollers on a common axle and in which the individual rollers may slip when subjected to undue torque resistance, thereby tending to avoid scuffing or damage to the rolled surface as when the front roller assembly is turned relative to the rear roller assembly to steer the machine.

Another object is to provide a road roller having close spaced pneumatic tired wheels individually clutched to a common axle.

Another object is to provide a roller construction wherein the center of rotation on turning of the machine is maintained centrally of two of the roller tires so that the machine is never turned on solely one wheel.

These and other objects of the invention will appear hereinafter in connection with the following description of the drawings, in which:

FIGURE 1 is a side elevational view of the road roller of the invention;

FIG. 2 is a top plan view of the roller of the invention with the pneumatic tired wheels of the front and rear roller assemblies shown in dotted lines;

FIG. 3 is a longitudinal sectional view of the front roller assembly taken on line 33 of FIG. 2 with parts in elevation;

FIG. 4 is a central vertical section taken on line 4-4 of FIG. 3; and

FIG. 5 is an end view taken on line 55 of FIG. 3 with parts broken away.

FIG. 6 is an enlarged sectional view of the threaded spanner nut at one end of the axle.

Referring to the drawings, the road roller illustrated comprises in general, a rear ballast section 1 supported on a frame 2, a forward ballast section 3 extending forwardly from section 1 and pivoted to a forward drive unit 4 having a frame 5.

The rear ballast section 1 comprises a tank for receiving water or the like to weight the same. The frame 2 which supports section 1 is in turn supported by suitable brackets 6 upon an axle at the rear end of the machine.

The rear roller assembly is comprised of a plurality of pneumatic tired wheels 8 mounted on the axle 7 for independent free rotation thereon, and which support the rear end of the machine.

The forward drive unit 4 has its frame 5 supported by suitable bearings 9 on an axle 19. The front roller assembly is comprised of a plurality of pneumatic tired wheels 11 mounted on the axle 16 to support the unit 4 on the road.

The front roller assembly is adapted to be driven by an engine 12 carried by unit 4. For this purpose a suitable transmission 13 on the engine shaft drives a sprocket 14 which in turn drives a sprocket 15 on the axle 10 by means of chain 16. A suitable brake 17 is adapted to reduce the rotation of sprocket 14 and may be actuated by hand lever 18 extending to a position convenient for the operator from seat 19 on unit 4.

The individual rollers 11 are driven from axle 10 by any suitable clutch means which will allow slippage of the same under undue torque load as in steering.

In the construction illustrated the hubs 20 of wheels 11 are mounted for free rotation on axle 19 and are spaced apart by intermediate clutch sleeves 21 splined to axle 10 by individual keys 22 riding in a spline groove 23 extending for the full length of the axle between bearings 9.

The end faces of hubs 20 and of sleeves 21 are suitably provided with frictional clutch elements so that when the hubs and sleeves are forced axially into pressure engagement the hubs are rotated with the sleeves and axle 10.

In the present construction the pressure engagement of the hubs 20 with the intermediate sleeves 21 is effected by confining the same upon axle 16 between two spanner nuts 24 threaded upon opposite ends of the axle inwardly of the end bearings 9, and then providing a suitable spring pressure tending to force the same together on the axle.

For this purpose one of the sleeves 21 is constructed in two parts, 25 and 26, each extending circumferentially of the axle 10 and bearing against the adjacent hub 20. Each part 25 and 25 is secured to rotate with axle 10 by the key 22 therefor.

The adjacent opposed faces of parts 25 and 26 have a plurality of circumferentially spaced complementary aligned circular recesses 27 therein for receiving compression coil springs 28. The number of springs 28 to be employed may var; with the needs, the construction shown having twelve recesses adapted to receive twelve springs. Each spring 28 is adapted to provide a clutch force of about one-thousand pounds. Where less than twelve springs 23 are employed they should be spaced as uniformly as possible about the axis of shaft 10.

' Under the influence of the springs 28 shown in the sleeve 21 located at the center of axle 10 the hubs 20 and sleeves 21 are biased longitudinally against the corresponding end nuts 24.

The nuts 24 may be suitably retained against unthreading tendencies by providing suitable washers 29 and 30 on opposite sides of each nut and keyed to the axle 10 to rotate therewith. Any suitable means may be provided to prevent turning of the nuts 24, except when being adjusted.

The nuts 24 should be tightened against inner Washers 30 until springs 28 effect the desired clutching pressure, just suificient for driving purposes, and that will provide slipping of the drive for any individual wheel '11 when subjected to excessive torque load, as when the machine is being turned. Adjustment of nuts 24 may effect a full clutching, a de-clutching or a clutch slippage position for the assembly, as desired.

Steering of the machine is effected hydraulically by pivoting the forward drive unit 4 relative to ballast secrod 35 effects turning of post 31 in pivot member 32 and rotation of the drive unit 4 relative to ballast section 3 to steer the road roller in the direction desired.

Actuation of piston 34 in cylinder 33 is effected by a valve 37 and hand lever 3-8 within reach of the operator and which admits fluid pressure to one selected end of cylinder '33 through conduit 39 and drains fluid from the other end of the cylinder through conduit 40, or vice versa.

\Any suitable number of rollers may be provided for the front roller assembly and also for the rear roller assembly. In the construction shown the front roller assembly has an even number of rollers and the steering axis provided by post 31 and pivot member 32 extends downwardly midway between the two spaced rollers at the center of the assembly. By reason of this construction the rollers adjacent the pivot axis are more free to turn without injuring the road surface, as might occur if a single roller were located directly beneath the pivot axis.

The rollers 8 of the rear roller assembly are staggered relative to the rollers 11 of the front assembly so that for straight rolling, each rear roller follows a path left unrolled by reasonof a space between a pair of front rollers. Where there is an even number of front rollers it is preferable to provide an odd number of'rear rollers, as shown.

The employment of two series of closely spaced pneumatic rollers each series being on a single axle with the rollers of one series staggered relative to those of the other series provides a roller which completely covers the surface to be rolled as stated for the solid drum type rollers, and at the same time provides the individual compacting action of the pneumatic tired wheels. The spacing between rollers on both the front and rear assemblies should be from twenty to thirty percent of the width of the tires.

The rear roller assembly has its rollers 8 mounted for free rotation on axle 7. Spacing of the rollers 8 may be provided by spacer sleeves 41 which may be free to rotate on the axle 7, if desired.

The axle 7 is clamped in end brackets 6 and need not rotate;

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. A pneumatic self-propelled road roller comprising a ballast section and a drive unit section, a rear axle, a series of more than two pneumatic rolls freely mounted on said rear axle in relatively closely spaced relation and supported by said axle from the ballast section to provide a drum-like pneumatic roller member at the rear of the road roller, a front axle, a second series of more than two pneumatic rolls freely mounted individually on said front axle in relatively closely spaced relation and supported by said front axle from the drive unit section to provide a drum-like pneumatic roller member at the forward portion of the road roller, an engine mounted on the drive unit section and connected to the front axle to rotate said front axle, each roll mounted on said front axle having a central hub with generally flat clutch surfaces on each side thereof and journaled on said axle, clutch means keyed to the front axle and including fiat frictional clutch members disposed between the flat surfaces of adjacent hubs, outward biasing means disposed on the axle between a pair of said rolls for urging the rolls of said series outwardly towards the ends of said axle, adjustable stop means secured to both ends of said axle and adjustable axially thereon to resist the axial thrust of said biasing means against the hubs and to selectively vary the force of said biasing means and the pressure between the clutch members and corresponding hubs to provide for individual wheel slippage on the torque loads above a predetermined drive torque.

2. A pneumatic self-propelled road roller comprising a ballast section and a drive unit section, a rear axle, a series of more than two pneumatic rolls freely mounted on said rear axle in relatively closely spaced relation and supported by said axle from the ballast section to provide a drum-like pneumatic roller member at the rear of the road roller, a front axle, a second series of more than two pneumatic rolls freely mounted individually on said front axle in relatively closely spaced relation and supported by said front axle from the drive unit section to provide a drum-like pneumatic roller member at the forward portion of the road roller, an engine mounted on the drive unit section and connected to the front axle to rotate said front axle, each roll having a central hub with generally flat clutch surfaces on each side thereof and journaled on said axle, flat' frictional clutch members disposed between the fiat surfaces of adjacent hubs, means for securing the clutch members to the axle to prevent relative rotation therebetween, outward biasing means disposed on the axle between a pair of said rolls for urging the rolls of said series outwardly towards the ends of said axle, adjustable stop means secured to both ends of said axle and adjustable axially thereon to resist the axial thrust of said clutch members against the hubs and to selectively vary the force of said biasing means and the pressure between the clutch members and corresponding hubs to provide for individual wheel slippage on the torque loads above a predetermined drive torque, said biasing means comprising two sleeves mounted axially on said axle and a circular array of compression spring members disposed intermediate portions of said sleeves for biasing said sleeves outwardly.

References Cited in the file of this patent UNITED STATES PATENTS 1,072,818 Buckwalter Sept. 9, 1913 1,206,895 Nilson Dec. 5, 1916 1,337,510 Frankman Apr. 20, 1920 1,494,881 Baines May 20, 1924 1,831,116 Huntley Nov. 10, 1931 1,839,981 Markey Jan. 5, 1932 2,024,184 Ritchie Dec. 17, 1935 2,199,649 Poulter May 7, 1940 2,213,383 Canfield Sept. 3, 1940 2,226,182 Ross Dec. 24, 1940 2,425,856 Ash Aug. 19, 1947 2,443,147 Ritchie June 8, 1948 2,510,817 Greiner et al. June 6, 1950 2,739,517 Roberts Mar. 27, 1956 

